CHEMICAL HAZARD - Lead poisoning

By Mayo Clinic Staff

Definition

Lead poisoning occurs when lead builds up in the body, often over a period of months or years. Even small amounts of lead can cause serious health problems. Children under the age of 6 are especially vulnerable to lead poisoning, which can severely affect mental and physical development. At very high levels, lead poisoning can be fatal.

Lead-based paint and lead-contaminated dust in older buildings are the most common sources of lead poisoning in children. Other sources include contaminated air, water and soil. Adults who work with batteries, do home renovations or work in auto repair shops also may be exposed to lead.

While treatment is available for lead poisoning, taking some simple precautions can help protect yourself and your family.

Symptoms

Initially, lead poisoning can be hard to detect — even people who seem healthy can have high blood levels of lead. Signs and symptoms usually don't appear until dangerous amounts have accumulated.

Lead poisoning symptoms in children

The signs and symptoms of lead poisoning in children may include:

• Developmental delay
• Learning difficulties
• Irritability
• Loss of appetite
• Weight loss
• Sluggishness and fatigue
• Abdominal pain
• Vomiting
• Constipation
• Hearing loss

Lead poisoning symptoms in newborns

Babies who are exposed to lead before birth may experience:

• Learning difficulties
• Slowed growth

Lead poisoning symptoms in adults

Although children are primarily at risk, lead poisoning is also dangerous for adults. Signs and symptoms in adults may include:

• High blood pressure
• Abdominal pain
• Constipation
• Joint pains
• Muscle pain
• Declines in mental functioning
• Pain, numbness or tingling of the extremities
• Headache
• Memory loss
• Mood disorders
• Reduced sperm count, abnormal sperm
• Miscarriage or premature birth in pregnant women

Causes

Lead is a metal that occurs naturally in the earth's crust, but human activity — mining, burning fossil fuels and manufacturing — has caused it to become more widespread. Lead was also once a key ingredient in paint and gasoline and is still used in batteries, solder, pipes, pottery, roofing materials and some cosmetics.

Lead in paint

The use of lead-based paints for homes, children's toys and household furniture has been banned in the United States since 1978. But lead-based paint is still on walls and woodwork in many older homes and apartments. Most lead poisoning in children results from eating lead-based paint chips.

Water pipes and imported canned goods

Lead pipes, brass plumbing fixtures and copper pipes soldered with lead can release lead particles into tap water. Although lead solder in food cans is banned in the United States, it's still used in some countries.

Traditional remedies

Some cases of lead poisoning have been traced to the use of certain traditional medicines, including:

• Greta or azarcon. This fine orange powder — also known as coral calcium and sea coral — is a Hispanic remedy taken for an upset stomach, constipation, diarrhea and vomiting. It's also used to soothe teething babies.
• Litargirio. Also known as litharge, this peach-colored powder is used as a deodorant, especially in the Dominican Republic.
• Ba-baw-san. This Chinese herbal remedy is used to treat colic pain in babies.
• Ghasard. A brown powder, ghasard is used as a tonic in India.
• Daw tway. A digestive aid used in Thailand, daw tway contains high levels of lead and arsenic.

Other sources of lead exposure

Lead can also sometimes be found in:

• Soil. Lead particles that settle on the soil from leaded gasoline or paint can last for years. Lead-contaminated soil is still a major problem around highways and in some urban settings. Soil close to walls of older houses may contain lead.
• Water. Copper plumbing soldered with lead is a source of contamination of household drinking water.
• Household dust. Household dust can contain lead from lead paint chips or from contaminated soil brought in from outside.
• Pottery. Glazes found on some ceramics, china and porcelain can contain lead that may leach into food.
• Toys. Lead is sometimes found in toys and other products produced abroad.
• Traditional cosmetics. Kohl is a traditional cosmetic, often used as eyeliner. Testing of various samples of kohl has revealed high levels of lead.

Risk factors

Factors that may increase your risk of lead poisoning include:

• Age. Infants and young children are more likely to be exposed to lead than are older children. They may chew paint chips, and their hands may be contaminated with lead dust. Young children also absorb lead more easily and sustain more harm from it than do adults and older children.
• Living in an older home. Although the use of lead-based paints has been banned since the 1970s, older homes and buildings often retain remnants of this paint. People renovating an older home are at even higher risk.
• Certain hobbies. Making stained glass requires the use of lead solder. Refinishing old furniture may put you in contact with layers of lead paint.
• Country of origin. People who live in developing countries are at higher risk of lead poisoning because those countries often have less strict rules regarding exposure to lead. American families who adopt a child from another country may want to have the child's blood tested for lead poisoning.

Lead can harm an unborn child, so pregnant women or women likely to become pregnant should be especially careful to avoid exposure to lead.

Complications

Exposure to even low levels of lead can cause damage over time, especially in children. The greatest risk is to brain development, where irreversible damage may occur. Higher levels can damage the kidneys and nervous system in both children and adults. Very high lead levels may cause seizures, unconsciousness and possibly death.

Preparing for your appointment

If you think you or your child has been exposed to lead, see your doctor or contact your local public health department. A blood test can help determine blood lead levels.

What you can do

Before your appointment, you might want to write a list of answers to the following questions:

• What symptoms or changes in behavior have you noticed?
• Do you or your child have other medical problems?
• What medications or supplements do you or your child take?

What to expect from your doctor

Your doctor may ask you some of the following questions:

• Have you recently moved to a different home or a different school?
• When was your house built? Are you renovating?
• Do you have a new job that might expose you to lead?
• Does your child have a sibling or playmate who has had lead poisoning?

Tests and diagnosis

Your child's doctor will likely recommend your child be tested for lead levels during routine well child exams. There is some disagreement in the medical community about how often or when a child should be screened for lead levels in their blood. Some experts feel children without any lead poisoning symptoms don't benefit from being tested for lead poisoning.

The Centers for Disease Control and Prevention (CDC) recommend doctors and parents follow the recommendations of their state or local health department. Some areas could potentially have a higher lead exposure risk, so certain areas may recommend more frequent testing. If your area doesn't have any specific lead testing recommendations, the American Academy of Pediatrics recommends your child be tested for lead levels at ages 1 and 2. Your doctor may also suggest lead screening if your child is older, but hasn't yet been screened for lead.

Doctors usually use a simple blood test to detect lead poisoning. A small blood sample is taken from a finger prick or from a vein. Lead levels in the blood are measured in micrograms per deciliter (mcg/dL). A level of 5 mcg/dL or higher indicates your child may have unsafe levels of lead in their blood and should have their blood tested periodically. If levels become too high — generally 45 mcg/dL or higher — your child should be treated.

Treatments and drugs

The first step in treating all degrees of lead poisoning is to remove the source of the contamination. If you can't remove lead from your environment, you may at least be able to reduce the likelihood that it will cause problems. For instance, sometimes it's better to seal in rather than remove old lead paint. Your local health department can recommend ways to identify and reduce lead in your home and community.

For children and adults with relatively low lead levels, simply avoiding exposure to lead may be enough to reduce blood lead levels.

Treating higher levels

For more-severe cases, your doctor may recommend:

• Chelation therapy. In this treatment, you take a medication that binds with the lead so that it's excreted in your urine.
• EDTA therapy. Doctors treat adults with lead levels greater than 45 mcg/dL of blood with one or more of three drugs, most commonly a chemical called ethylenediaminetetraacetic acid (EDTA). Depending on your lead level, you may need more than one treatment. In such severe cases, however, it may not be possible to reverse damage that has already occurred.

Children may need chelation therapy at lower levels than adults do.

Prevention

You can take some simple measures to help protect you and your family from lead poisoning. These may include:

• Wash hands and toys. To help reduce hand-to-mouth transfer of contaminated dust or soil, wash your children's hands after outdoor play, before eating and at bedtime. And wash their toys regularly.
• Clean dusty surfaces. Clean your floors with a wet mop and wipe furniture, windowsills and other dusty surfaces with a damp cloth.
• Run cold water. If you have older plumbing containing lead pipes or fittings, run your cold water for at least a minute before using. Don't use hot tap water to make baby formula or for cooking.
• Prevent children from playing on soil. Provide them with a sandbox that's covered when not in use. Plant grass or cover bare soil with mulch.
• Eat a healthy diet. Regular meals and good nutrition may help lower lead absorption. Children especially need enough calcium and iron in their diets.

Home renovation

If you're doing minor remodeling or touch-up work in an older house with lead-based paint, take precautions.

• Don't attempt to remove the lead paint by sanding.Sanding surfaces painted with lead is hazardous because it generates large amounts of small particles.
• Don't use an open-flame torch to remove paint. The flame produces lead particles small enough to inhale.
• Cover old paint. Removing old lead paint may not always be possible. If the paint is on tight, without many chips, you can paint over it. You can also use paneling, drywall or encapsulation, which is similar to a very thick coat of paint.
• Wear protective equipment and clothing. Change your clothes, take a shower and wash your hair before leaving the job. Don't shake out work clothes or wash them with other clothes.
• Be careful where you eat. Don't eat or drink in an area where lead dust may be present.

Source: http://www.mayoclinic.org/